The US Army field manual FM 1-02 (FM 101-5-1) describes an \"air assault operation\" as an operation in which assault forces (combat, combat support, and combat service support), using the firepower, mobility, and total integration of helicopter assets, maneuver on the battlefield under the control of the ground or air maneuver commander to engage and destroy enemy forces or to seize and hold key terrain usually behind enemy lines.
Due to the transport load restrictions of helicopters, air assault forces are usually light infantry, though some armored fighting vehicles, like the Russian BMD-1 are designed to fit most heavy lift helicopters, which enable assaulting forces to combine air mobility with a certain degree of ground mechanization. Invariably the assaulting troops are highly dependent on aerial fire support provided by the attack helicopters, armed helicopters and/or fixed-wing aircraft escorting them. A concept called mounted vertical maneuver requires the ability to transport light, motorized, or medium-weight mechanized force by VTOL or super STOL aircraft.
Air assault should not be confused with air attack, air strike, or air raid, which all refer to attack using solely aircraft (for example bombing, strafing, etc.). Moreover, air assault should not be confused with an airborne assault, which occurs when paratroopers, and their weapons and supplies, are dropped by parachute from transport aircraft, often as part of a strategic offensive operation.
Air assault units can vary in organization; using helicopters not only in transport but also as close air fire support, medical evacuation helicopters and resupply missions. Airmobile artillery is often assigned to air assault deployments. Units vary in size, but are typically company tobrigade sized units.
One specific type of air assault unit is the US Army air cavalry. It differs from regular air assault units only in fulfilling a traditional cavalry reconnaissance and short raids role. Britain's 16 Air Assault Brigade was formed in 1999 following an amalgamation of elements of 5th Infantry Brigade (5 Airborne Brigade) and 24 Airmobile Brigade, bringing together the agility and reach of airborne forces with the potency of the attack helicopter. Similarly, the US 101st Airborne Division was originally classed as airborne, then airmobile and now air assault.
Air mobility has been a key concept in offensive operations since the 1930s. Initial approaches to air mobility focused on parachutists and the use of military gliders. During World War II many assaults were done by military gliders. The World War Two era German Fallschirmjäger, Brandenburgers, and the 22nd Air Landing Division glider borne paras laid the foundation for modern day air assault operations. In 1941 the U.S. Army quickly adopted this concept of offensive operations initially utilizing wooden gliders before the development of helicopters. Following the war, faster aircraft led to the abandonment of the flimsy wooden gliders with the then new helicopters taking their place. Four YR-4B helicopters saw limited service in the China Burma India theatre with the 1st Air Commando Group
In 1943 the Germans conducted the Gran Sasso raid which implemented many aspects of the air assault concept. Another example was the German Brandenburgers' glider borne operation at Ypenburg during World War Two.
On November 5, 1956, the Royal Marines' 45 Commando performed the world's first combat helicopter insertion with air assault during an amphibious landing as part of Operation Musketeer, in Suez, Egypt. 650 marines and 23 tons of equipment were flown in ten Westland Whirlwind Mark 2s of 845 Naval Air Squadron from the deck of HMS Theseus, and six each Whirlwinds and Bristol Sycamore HC.12s and HC.14s off HMS Ocean's embarked Joint Experimental Helicopter Unit (JEHU) (Royal Air Force).
The plan was to use the helicopters to drop No. 45 Commando at Raswa, to the south of Port Said, in order to secure two vital bridges. Last-minute concerns about their vulnerability to ground fire meant that they were replaced in this role by French paratroops who conducted a daring low-level drop on 5 November, securing one of the two bridges intact. Instead No. 45 Commando was landed the following day, disembarking close to the seafront in the aftermath of the seaborne landing that had secured the area. This first-ever operational use of helicopters to land troops during an amphibious assault proved successful. With their carriers lying nine miles offshore, the marines were landed far more quickly than could have been achieved using landing craft, and without the need to get their boots wet. However ... they landed the marines in much the same place that old style landing craft would have put them.
In 1956, the United States Marine Corps executed the first Division-strength exercise of vertical envelopment when the 1st Marine Division was helicopter-lifted from converted WWII jeep carriers to landing sites at Camp Pendleton, CA, U.S. Marine Corps Base. One of the ships utilized for this exercise was the USS Thetis Bay. This exercise was the culmination of the Marines' developing strategy of vertical envelopment rather than amphibious assaults on heavily defended beaches. The maneuvers were well-covered by the media of the time, including LIFE Magazine. The Marine Corps subsequently adopted this method as standard operating procedure after proving that helicopters could be used to transport very large numbers of troops and large amounts of supplies in a timely fashion.
Operation Deep Water was a 1957 NATO naval exercise held in the Mediterranean Sea that involved the first units of the United States Marine Corps to participate in a helicopter-borne vertical envelopment operation during an overseas deployment.
U.S. Army CH-21 helicopter transports arrived in South Vietnam on 11 December 1961. Air assault operations using Army of the Republic of Vietnam (ARVN) troops began 12 days later in Operation Chopper. These were very successful at first but the Viet Cong (VC) began developing counter helicopter techniques, and at the Battle of Ap Bac in January 1963, 13 of 15 helicopters were hit and four shot down. The Army began adding machine guns and rockets to their smaller helicopters and developed the first purpose built gunship with the M-6E3 armament system.
U.S. Marine helicopter squadrons began four-month rotations through Vietnam as part of Operation SHUFLY on 15 April 1962. Six days later, they performed the first helicopter assault using U.S. Marine helicopters and ARVN troops. After April 1963, as losses began to mount, U.S. Army UH-1 Huey gunships escorted the Marine transports. The VC again used effective counter landing techniques and in Operation Sure Wind 202 on 27 April 1964, 17 of 21 helicopters were hit and three shot down.
The 2nd Battalion 3rd Marines made a night helicopter assault in the Elephant Valley south of Da Nang on 13 August 1965 shortly after Marine ground troops arrived in country. HMM-361 commanded by LtCol Tom Ross. On 17 August 1965 in Operation Starlite the 2nd Battalion 4th Marines landed in three helicopter landing zones (LZs) west of the 1st VC Regiment in the Van Tuong village complex, 12 miles (19 km) south of Chu Lai, while the 3rd Battalion 3rd Marines used seaborne landing craft on the beaches to the east. The transport helicopters were 24 UH-34s from HMM-361, HMM-261 and HMM-161 in relief, escorted by Marine and Army Hueys from VMO-2 and VMO-6 led by Maj Donald G. Radcliff, US Army who was killed in action. VC losses were 614 killed, Marine losses were 45 KIA and 203 WIA.
The first unit of the new division to see major combat was the 1st Battalion, 7th Cavalry Regiment, 1st Cavalry Division, led by Lieutenant Colonel Harold G. Moore. The 7th Cavalry was the same regiment that Custer had commanded at the ill-fated Battle of the Little Bighorn. On November 14, 1965, Moore led his troops in the first large unit engagement of the Vietnam War, which took place near the Chu Pong massif near the Vietnam-Cambodia border. It is known today as the Battle of Ia Drang Valley, and is considered to be the first large scale helicopter air assault.
On a practical level, virtually any light infantry formation can instantly become \"airmobile\" simply by dividing the assault elements into \"chalks\" (aircraft load designations pertaining to order of loading and type of aircraft), embarking them on the aircraft, transporting them to the objective/assembly area, and inserting/disembarking them into a landing zone, etc. However, true \"air assault\" organizations are specialized light infantry (much like airborne troops), who are trained, organized, and equipped specifically to perform the complex, rapid, and dynamic tasks inherent in air assault vice simply being transported by aircraft. Perhaps a rough comparison can be made between \"motorized\" and \"mechanized\" infantry. Any light infantry unit can be transported by truck (viz., \"motorized\"), however, \"mechanized\" infantry are specifically trained, organized, and equipped to conduct operations in close-coordination with tanks.
The airmobile warfare tactics used by Portugal, Rhodesia and South Africa had many similar characteristics. The air forces of the three countries also used the same types of helicopters (mainly Alouette III and later, regarding Portugal and South Africa, SA 330 Puma), and there were military cooperation agreements and sharing of experience between the three powers, including the secret Alcora Exercise.
Portuguese, Rhodesian and South African airmobile tactics often involved air assaults done by small units of special forces or light infantry, transported in four or five Alouette III helicopters. Assaults were often supported by an Alouette III armed with a side-mounted 20 mm MG 151 autocannon. This helicopter was nicknamed Helicanhão (heli-cannon) by the Portuguese and K-Car by the